In power systems, circuit breakers are used for connecting and disconnecting a load. During this process, active elements of the circuit breaker either interrupt or incept high current, causing stresses in the circuit breaker as well as connected power system components. The flow of the high current can be limited by closing and opening the circuit breaker at a specific instance on a source voltage waveform. A plurality of techniques are known for controlling the opening or closing of the circuit breaker in order to prevent generation of a transient phenomenon. Such techniques rely on usage of devices that perform synchronized switching control. One such device is a point on wave controller.
A point on wave controller is used for controlling a switching instance of the circuit breaker. On receiving a command from a bay control unit, the point on wave controller advances the command to achieve closing or opening at an instance to minimize the current, depending on the load connected, considering all the delay caused until the primary contact of the circuit breaker is closed or separated depending on whether it is a close or open operation. The point on wave controller detects the opening or closing actuation time (also referred to as operating time) of the circuit breaker and calculates a time for switching in respect of the opening or closure command signal of the circuit breaker to ensure switching on a particular point on the voltage waveform. Based on a calculated time, the point on wave controller controls the output timing of the opening or closure command signal. For calculating the synchronization delay time, the point on wave controller utilizes a plurality of inputs such as load characteristics, source voltage, source current, load voltage, ambient temperature, drive pressure of the circuit breaker, etc. By observing the source voltage, the point on wave controller predicts the future points on the source voltage waveform and will accordingly release the open or close command of the operating coils to the circuit breaker.
Currently, there is an increasing demand for using point on wave controllers for charging and discharging of static loads, such as reactors, capacitors, etc., and for energizing and de-energizing equipment such as transformers, lines, etc. so as to ensure proper switching operations. Due to this increasing demand, point on wave controllers are being used across all the bays of the power system including the transfer bay. However, currently the accuracy of the point on wave controller present on the transfer bay is lower than those of the point on wave controllers connected to the bays. Additionally, point on wave switching on the transfer bay can be procedurally complex. Therefore, when a load is transferred to the transfer bay, often improper switching operation occurs causing a reduction in life expectancy of the circuit breaker.
In light of the foregoing discussion, a method and system are disclosed that can address the issues mentioned.